Development of a Plasmodium PCR for monitoring efficacy of antimalarial treatment

We report in this work a highly sensitive and nonradioactive PCR method for the detection of the four species of parasite causing human malaria. Plasm odium-specific primers corresponding to the small-subunit rRNA genes of the malaria parasite were used, and a 291-bp fragment was amplified. Our resul ts showed a high specificity for the four human Plasmodium species, and we were able to detect one parasite in 50 mu l of whole blood. The responses o f 12 patients infected with Plasmodium falciparum to antimalarial therapy w ere monitored by PCR diagnosis and examination of thick blood film for at l east 20 min by an experienced microscopist. For one patient this study allo wed early diagnosis of therapeutic failure, confirmed 7 days later by exami nation of the thick blood film. A total of 134 samples were examined; 94 we re positive by PCR, and among these 68 were positive by thick blood film ex amination. The sensitivity of the thick blood film was 72.3% compared to PC R and 60.7% compared to dot blot hybridization.